1. Field of the Invention
The present invention relates to an improvement of a lubrication device for an engine and an outboard engine system, comprising: an oil pan which is disposed at a lower portion of an engine and stores lubrication oil; an oil pump which is disposed above the oil pan and driven by the engine; a suction oil passage which guides the oil in the oil pan to a suction port of the oil pump; a supply oil passage which guides the oil discharged from a discharge port of the oil pump to lubrication parts of the engine; and a strainer which filters the oil sucked from the oil pan by the oil pump.
2. Description of the Related Art
Such a lubrication device for an engine is known as disclosed in Japanese Patent Application Laid-open No. 7-305617 and Japanese Patent Application Laid-open No. 58-183384.
In the conventional lubrication device for an engine, a strainer is mounted to a lower end of a suction pipe disposed in an oil pan. In this device, because the strainer comprises a strainer case directly connected to an opening at the lower end of the suction pipe, and a filter net provided so as to extend in the strainer case, the strainer is heavy and easily swings along with the suction pipe with its own inertia force. Thus, in order to prevent the swing, the suction pipe is supported by a stay extending from an inner wall of the oil pan. In this way, the conventional device has a large weight and a complicated structure.
Further, in the conventional lubrication device for an engine and an outboard engine system, a cooling water passage of the engine is disposed in a central portion of the oil pan so as to pass through the oil pan so that cooling water cools the oil stored in the oil pan. However, in order to cool the entire oil stored in the oil pan with the cooling water of the engine, a large amount of cooling water is required, leading to an extremely low cooling efficiency.